JobScheduler should not load job documentations on start-up but on demand

Current Situation

• On start-up the loading of job description elements from the job configuration affects the performance if larger documentation is included, e.g. by using <include> elements.

Desired Behavior

• The JobScheduler should not load the contents of files specified by the <include> element within <descriptions> on start-up. However, when being used by the XML API call <show_job job="..." what="description"/> then any included content shall be resolved.
• We assume that we have a job configuration with

  ...
  <description>
     <include file="jobs/myDocu.html"/>
  </description>
  ...
  

• The JobScheduler should not load the included file on start-up.
• The command <show_job job="..." what="description"/> returns all included content.

Maintainer Notes

• The contents of an included description is provided exlusively if the request includes the what="description" attribute.
• Therefore the behavior remains unchanged.